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  Ti'Misactions. 
  — 
  Zoology. 
  

  

  their 
  appearance.* 
  Agassiz 
  observes 
  that 
  they 
  are 
  very 
  slow 
  in 
  expanding 
  

   themselves. 
  When 
  expanded 
  they 
  have 
  no 
  resemblance 
  to 
  true 
  polyps. 
  

   There 
  is 
  simply 
  a 
  fleshy 
  tube 
  with 
  a 
  mouth 
  at 
  top 
  and 
  a 
  few 
  small 
  rounded 
  

   prominences 
  in 
  place 
  of 
  tentacles, 
  four 
  of 
  them 
  sometimes 
  largest. 
  The 
  

   corals 
  of 
  the 
  Millejjoi'cs 
  are 
  solid 
  and 
  strong, 
  as 
  much 
  so 
  as 
  any 
  in 
  coral 
  

   seas. 
  They 
  have 
  generally 
  a 
  smooth 
  surface, 
  and 
  are 
  always 
  without 
  any 
  

   prominent 
  calices, 
  there 
  being 
  only 
  very 
  minute 
  rounded 
  punctures 
  over 
  

   the 
  surface 
  from 
  which 
  the 
  animals 
  show 
  themselves. 
  The 
  cells 
  in 
  the 
  

   coralline 
  are 
  divided 
  parallel 
  to 
  the 
  surface 
  by 
  very 
  thin 
  plates 
  or 
  tables. 
  

   The 
  MilleporcE 
  are 
  very 
  abundant 
  corals. 
  They 
  extend 
  outside 
  the 
  tropics 
  

   in 
  Australia 
  as 
  far 
  south 
  as 
  Moreton 
  Bay. 
  In 
  the 
  West 
  Indies 
  they 
  con- 
  

   tribute 
  largely 
  to 
  the 
  formation 
  of 
  the 
  reefs. 
  

  

  According 
  to 
  Professor 
  Verrill, 
  there 
  are 
  thirteen 
  species 
  of 
  the 
  genus 
  

   MilleporcB 
  known, 
  but 
  two 
  of 
  these, 
  M. 
  monilifornis 
  and 
  complanata, 
  are 
  sup- 
  

   posed 
  to 
  be 
  varieties 
  of 
  M. 
  alcicornis 
  and 
  2?licata 
  respectively. 
  Without 
  any 
  

   exception 
  they 
  are 
  all 
  tropical 
  and 
  living. 
  They 
  occur, 
  as 
  already 
  stated, 
  

   in 
  the 
  West 
  Indies, 
  and 
  also 
  in 
  the 
  Indian 
  Archipelago, 
  the 
  Ked 
  Sea, 
  

   Mauritius, 
  and 
  the 
  Fiji 
  Islands. 
  The 
  occurrence, 
  therefore, 
  of 
  a 
  species 
  in 
  

   New 
  Zealand, 
  and 
  in 
  so 
  cold 
  a 
  latitude 
  as 
  Foveaux 
  Strait, 
  is 
  most 
  singular 
  

   and 
  interesting. 
  Such 
  facts 
  have 
  a 
  tendency 
  to 
  make 
  us 
  doubt 
  some 
  of 
  the 
  

   geological 
  conclusions 
  at 
  which 
  we 
  sometimes 
  arrive. 
  A 
  few 
  years 
  ago, 
  

   the 
  discovery 
  of 
  two 
  reef-building 
  genera 
  of 
  corals 
  in 
  the 
  tertiary 
  beds 
  of 
  

   Tasmania 
  was 
  looked 
  upon 
  as 
  the 
  evidence 
  of 
  an 
  almost 
  tropical 
  climate. 
  

   Indeed, 
  a 
  discussion 
  ensued 
  at 
  the 
  Geological 
  Society 
  of 
  London 
  as 
  to 
  

   whether 
  it 
  might 
  not 
  be 
  presumed 
  that 
  the 
  axis 
  of 
  the 
  earth 
  had 
  shifted 
  

   since 
  these 
  beds 
  were 
  deposited. 
  The 
  coral 
  to 
  which 
  I 
  am 
  now 
  drawing 
  

   attention 
  is 
  truly 
  of 
  a 
  reef-building 
  kind, 
  but 
  I 
  am 
  not 
  aware 
  whether 
  it 
  

   forms 
  reefs. 
  This 
  would 
  be 
  a 
  very 
  interesting 
  subject 
  of 
  enquiry. 
  I 
  have 
  

   named 
  the 
  species 
  Millepora 
  undulosa, 
  from 
  the 
  peculiar 
  undulating 
  character 
  

   of 
  the 
  surface 
  of 
  the 
  branches. 
  It 
  is 
  thus 
  described 
  : 
  — 
  

  

  Millepora 
  undulosa, 
  n.s. 
  

   Corallum 
  arborescent, 
  very 
  much 
  branched, 
  branches 
  crowded 
  cylindrical, 
  

   spreading 
  in 
  all 
  directions, 
  generally 
  somewhat 
  flattened 
  at 
  the 
  extremity 
  

   and 
  with 
  a 
  short 
  bifurcation, 
  often 
  coalescent, 
  either 
  along 
  the 
  whole 
  side 
  

   of 
  the 
  branch 
  or 
  just 
  at 
  a 
  point 
  of 
  contact, 
  or 
  by 
  sending 
  out 
  a 
  short 
  small 
  

   branchlet 
  from 
  one 
  stem 
  to 
  another. 
  The 
  whole 
  surface 
  of 
  the 
  branches 
  

   undulating 
  with 
  broad 
  but 
  not 
  deep 
  rugosities; 
  cells 
  exceedingly 
  small, 
  

   crowded, 
  giving 
  a 
  spongy 
  appearance 
  ; 
  colour, 
  dull 
  reddish-brown. 
  Alti- 
  

   tude 
  of 
  specimen 
  described 
  80 
  ; 
  width 
  at 
  farthest 
  extremity 
  of 
  branches 
  

  

  * 
  Corals 
  and 
  Coral 
  Islands, 
  by 
  James 
  D. 
  Dana, 
  English 
  Edition, 
  p. 
  79. 
  

  

  